Thermostatically controlled crankcase ventilating inlet



Aug. 2, 1932. 1 B, ELLIS THERMOSTATICALLY CONTROLLED CRANK CASE VENTILATING INLET Filed. July 26, 1930 5 Sheets-Sheet l glwuewtoz L. B. ELLIS 1,369,553

THERMOSTATICALLY CONTROLLED CRANK CASE VENTILATING INLET Aug. 2, 1932.

3 Sheets-Sheet 2 Filed July 26, 1950 m M M L.El ELLJS Aug. 2, 1932.

THERMOSTATICALLY CONTROLLED CRANK CASE VENTILATING INLET Filed July 26, .1930 3 Sheets-Sheet 3 sential in modern engines,

- .3 temperature Patented Aug. 2, 1932 LooKlwoon B. FL'JLIS, OF BIRMINGHAM, MICHIGAN, ASSIGNOR ,TO GENERAL MOTORS CORPORATION, OF DETROIT, MICHIGAN, A CORI ORATION OF DELAWARE THERMOST'ATICALLY CONTROLLED CRANKCASE VENTILATING INLET Application filed July 26,

This is an improvement on the crankcase ventilating system described and claimed in my prior application, Serial No. 4 1,761, filed July 20, 1925. While the invention is shown specifically applied to this type of ventilating system, it is equally applicable to other systems for passing a stream of air through the crankcase.

The primary object of causing a stream of air to flow through the crankcase of an internal combustion engine is to set up an evaporative action that will remove water and other diluents from the lubricating oil contained in the crankcase. These diluents enter the crankcase by leakage past the pistons, and not only dilute the oil thereby reducing its viscosity to an undesirable extent, but also the water of combustion formed in the combustion chamber unites in the crankcase with the sulphur occurring as an impurity in the motor fuel and forms sulphurous acid which has a corrosive action on the motor parts. While crankcase ventilation is therefore very desirable, and, indeed, es-

the difficulty arises that if too much air is drawn through the crankcase the thrashing action of the revolving crankshaft and connected parts will create an oily mist increasing the evaporation and causing more oil to be. drawn out out of the engine. Furthermore the building up of high pressure in the crankcase tends to force oil past the pistons more rapid-.

ly thereby also increasing consumption.

I is have made use of this change in temperature to prevent excessive loss of oilat the higher engine speeds. I have done this by providing my crankcase ventilating system with a thermostatic control so that as the engine increases the ventilation is gradually shut E. The design is preferably such that at higher engine speeds there is no flow of air through the crankcase, but merely suction applied to the crankcase so which serves to draw'off the vapors that blow This lose of oil is especially marked at the i 1930. Serial .No. 471,001.

by the pistons. The resulting subatmos pheric pressure in the crankcase serves to pre vent leakage of oil throughthe joints.

I have preferred to apply my controlin the form of a thermally operated valve at the crankcase air inlet as by this means the suction usually supplied at the outlet is availv able to draw out the fumes even when the valve is closed. With this system it is obvious that with the valve open there may be superatmospheric pressure in the crankcase, while with the valve closed the pressure becomes subatmospheric with the advantages outlined above.

Figure 1 is a vertical sectional view of my improvedengine with certain parts omittedthat have nothing to do with my invention.

Figure 2 is a side elevation of the engine.

Figure 3 is an enlarged detail view showing the thermostatically controlled air inlet looking at it from the inside of the crankcase.

Figure 4 is a Figure 3.

Figure 5 is a fragmentary-side elevation, 7 partly in section, of a slightly modified form of crankcase inlet and thermostatic control valve therefor. V

Figure 6 is an elevation of the control valve of Figure 5 in place in the crankcase inlet as viewed from the inside of the crank-- case.

Figure 7 is a section on line 7 -7 of Figure 6. V

Figure 8 is a section on line 8-8 of Figure 5.

I have shown my ventilating system applied to a well known V-type engine. 2 indicates the crankcase serving as an oil reservoir and housing the crankshaft 41. 6 and 8 indicate the banks of cylinders arranged according to Cadillac practice at a 90 angle to each other. Air enters the crankcase through inlet 10 to which is connected by conduit 12'an air cleaner 14 of any desired type. The air entering the crankcase is, as 1 described in my prior application, entrained by the revolving crankshaft and discharged through apertures 15 provided in the cylinder walls, preferably within the. stroke'of 100 view taken on line 44; of

the piston, and on the sides of the cylinders at the inside of the V. Pipes 18 connnuni cate with the valve chambers at the rear of the engine and extend to a point below the 5 usual dust pan where they are subjected to the aspirating action of the passing air currents. The design as so far described is substantially the same as that disclosed and claimed in my prior application.

At 20 I have indicated my ventilator control valve which consists of a plate or "flap valve 22 mounted on the end of a bimetallic element in the form of a spring blade 24 which is fastened at one end to the engine crankcase. If desired, the inlet 10 may carry the valve and to facilitate assembly may be made removable from the crankcase. I have indicated in dotted lines the open position of the valve.

In operation at the lower temperature air enters the crankcase through the air cleaner 14, pipe 12, and inlet 10, is whirled about by thecrankcase and mixed with the lubricating oil, effecting evaporation of diluents The air together with the diluents then discharged under the pressure built up by the whirling action through the openings 15 into the valve compartments, and out of the valve compartments through the outlet tubes 18 beneath the car so that the odors do'notreach the occupants of the vehicle. As the engine heats up, as a result of increased speed or load, the bimetallic thermostat 2 lgradually moves toward closed position, and at temperatures corresponding to the higher engine speeds, completely shuts off the passage 10 so that air no longer flows through thecrankcase. Under these conditions the suction on the outlets 18 caused by the rush of air created by'the travel of the car effects the withdrawal of the hot gases that blow by the pistons. The blow by is excessive at the higher speeds and powers, and by cutting off the air inlet by operation of my thermostatic control the pumping action of the crankcase and the suction on the crankcase outlet are left with sufficient capacity to handle it.

The resultant reduction in pressure in the crankcase prevents the loss of oil by leakage through the joints and also reduces the amount of oil passing the pistons. The oil consumption is thereby greatly reduced. even when the difference in pressure is very slight.

In Figures 5 to 8 l have illustrat d an improved form of ventilator control valve.

'Here 2 represents a portion of the engine crankcase, 26 the exhaust manifold secured in place to one of the cylinder blocks illustrated fragmentally at 28. 30 indicates the To the inle' secured 34 and the crankcase inlet. To the fitting 34: is secured the air inlet pipe 36 the upper end 55 of which fits within the stove 58 cast integi,se9,553

rally with the exhaust manifold 26. Obviously, if preferred, the stove may be in the form of a stamping secured to the exhaust manifold or other hot part of the engine. Also an air cleaner may be applied to the stove if desired.

To the plate 32 is secured the member 42 in the form of a stamping shaped at its lower end to provide louvers 4.4 admitting air to the crankcase in a direction tangential to the path of rotation of the engine crankshaft 4:. The plate 32 is apertured at 46 in line with the member 42 and in the aperture is mounted valve 48 centrally pivoted on pintle 50. One end of the pintle 50 is bent upon itself, forming a crank 51 over which is hooked the end 52 of a. bimetallic thermostat 54, the other end of which is bolted to a lateral flange 56 on the member 42.

This form of the device operates in sub stantially the same manner as the first form. Hot air is supplied to the crankcase from stove 38, through inlet pipe 8'6, fitting 34-, aperture 46, and louvers 44. When the engine temperature rises, the bimetallic then mostat '54; becomes warped, the free upper end moving in toward the axis of the crankshaft, and carrying with it the crank 51 on pintle 50, thereby swinging the valve 48 to closed position.

The purpose of the arrangement of leuvers is to increase the suction of the crankshaft which is much more effective when rotating past a series of small openings than when passing a single large opening. The large opening permits eddy currents which interfere with the inward flow of air. This construction permits the use of a balanced valve as illustrated at as.

I have found with my improved ventilating system it is possible to get rid of all traces of water and consequently prevent the destructive corrosive action. My thermostatic control prevents distillation of the lighter fractions of the lubricating oil at the higher temperatures and so saves oil.

Obviously the system is capable of considerable change in detail. It is of course, not essential that the crankcase air be discharged through holes in the cylinder walls, although this is desirable as the vapors lea-king past the pistons are swept out before they have opportunity to enter the crankcase. If desired, the thermostatic valve could be placed in the crankcase outlet instead of in the inlet, but this is undesirable for at the higher engine speeds the fumes would then be discharged into the hood compartment and from there would find access to the interior of the car to the annoyance of the occupants. The crankcase air inlet and outlet may be arranged in other locations than those shown as may be desirable in the particular engine installation. For example in the case of overheadvalve engines in which the valve housing is connected with the crankcase through the pushrod chambers, the crankcase outlet would, of course, lead from the valve chamber. a

I claim:

1. A fitting for a crankcase air inlet in the form of a plate adapted to be secured to the inlet and having an aperture therein, a shield for the aperture secured to the plate and arranged to extend inwardly of the crankcase, a valve pivoted to the plate centrally of the aperture, and a thermostat extending inwardly of the crankcase and adapted to be secured at one end to the fitting and at the other end to the valve for operating the latter to close the aperture upon increase in engine temperature.

2. A fitting for a crankcase air inletin the form of a plate adapted to be secured to the inlet and having a central aperture therein, a louvered shield secured to the plate over the aperture, a valve arranged to close the aperture, and a thermostat secured to the fitting and arranged to operate the valve.

3. A fitting for a crankcase air inlet in the form of a plate adapted to be secured to the inlet and having a central aperture therein, a louvered shield secured to the plate and over the aperture, a valve pivoted in the plate and overlying the aperture, and a bimetallic thermostatic element, secured to the plate at one end and the valve at the other end for operating the latter.

4. A fitting for a crankcase air inlet in the form of a plate adapted to be secured over the inlet and having an aperture therein, a louvered shield secured to the plate and over the aperture, a valve pivoted in the plate and arranged to be moved to close the aperture, and said valve being provided with a pintle having an end extended to form a crank, and a thermostat secured at one end to the plate and at the other end to the crank for operating the valve.

5. A fitting for a crankcase air inlet in the form of a plate arranged to be secured over the inlet and provided with louvered openings, facing, when the plate is secured in place, in the direction of crankshaft rotation and tangentially to its path of movement.

6. An engine having a crankshaft, and a crankcase serving as a lubricant reservoir and provided with an air inlet and an air outlet, said air inlet being arranged so as to be subject to the aspirating action of the revolving crankshaft, said inlet being in the form of narrow louvers extending in a direction parallel to the axis of the crankshaft and opening in the direction of air flow created by the revolving shaft.

7 The combination of a crankcase provided with an air inlet and an air outlet, means for producing a circulation of air through the crankcase from the inlet to the outlet, a valve in the form of a plate overlying the inlet, and a bimetallic thermostat mounted within the crankcase adjacent the air inlet and having a free portion thereof connected to the plate, said thermostat h through the crankcase from the inlet to the outlet, and athermostatic control for said 1nlet comprlslng a mounting plate secured to the crankcase adjacent said inlet, a bimetallic thermostat within the crankcase above the level of the oil therein secured to said plate and having a free portion extending adjacent said inlet, and a valve carried by said free portion and overlying said inlet, said thermostat being arranged to close said inlet upon increase in temperature in the crankcase.

9. The combination of a crankcase provlded with an air inlet and an air outlet, means for producing a circulation of air through the crankcase from the inlet to the outlet, and a thermostatic control for said inlet including a thermally responsive element located within the crankcase wholly above the level of the oil therein, said element being connected to said crankcase and having a free portion, a valve connected to' said free portion and overlying said inlet, sa1d element being arranged to operate said valve to close the inlet upon increase in temperature of the crankcase vapors.

In testimony whereof I affix my signature.

LOCKWOOD B. ELLIS. 

